A high low-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio as a potential risk factor for corticosteroid-induced osteonecrosis in rabbits

Objective. This study was designed to determine the potential risk factors for corticosteroid-induced osteonecrosis (ON) based on lipid metabolism, using a rabbit ON model. Methods. Blood samples were obtained from 38 rabbits, which then received a single intramuscular injection of 20 mg/kg methylprednisolone acetate. Four weeks after the injection, the femora and humeri were examined histopathologically for the presence of ON, and the sizes of the bone marrow fat cells were also measured. Results. Rabbits with and without ON differed significantly in the ratio of low-density lipoprotein cholesterol to high-density lipoprotein cholesterol (LDL/HDL cholesterol ratio), which is considered to be a serological marker of lipid transport (P = 0.026). The marrow fat cells were significantly larger in the rabbits with ON than in those without ON (P < 0.0001). Conclusion. A higher LDL/HDL cholesterol ratio was significantly associated with the development of ON, and such an elevated ratio may partly contribute to the increased size of marrow fat cells.